Foot measuring method

ABSTRACT

There is provided a foot measuring system that includes a support surface for a foot, a plurality of movable measurement structures, an inflatable diaphragm for contacting the first end of each structure and forcing a movement of each structure from an initial position toward a measurement position, a measurement device for measuring the measurement position relative to the initial position of each structure, after the movement of each structure, to determine a shape of the foot. Each structure of the plurality of movable structures has a first end and a second end. The present invention also includes a method for measuring the contours of a foot.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is claiming priority of U.S. Provisional PatentApplication Ser. No. 60/653,026, filed on Feb. 15, 2005, the content ofwhich is herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to measurement devices and methods, andmore particularly, to devices and methods for foot contour measurement.

2. Description of the Related Art

Foot contour measurement methods typically consist of sampling thesurface of the foot using either mechanical (such as plaster et al.),electronic, electromechanical or electro-optical means.

A preferred device is manufactured by the assignee of this application.The same also holds a number of patents covering various methods tomeasure feet and to fabricate a custom machined insoles for the foot.One such device, a “Contact Digitizer”, uses regularly spaced gauge pinsthat are urged upwards under the subject foot, as disclosed in U.S. Pat.Nos. 4,449,264, 4,454,618, 4,517,696, 4,876,758, and 5,941,835. Thesegauge pins are measured for position relative to a datum surface that isthen processed to produce a digital model of the undersurface of thefoot. This device is preferred over other technologies due to theability of the gauge pins to deflect the soft tissue encountered whenupwardly urged against the undersurface of the foot. The machinetherefore makes allowances for the areas of the foot with soft tissue orwhere there may be underlying bone structure. This produces a data setwhich incorporates these allowances. When this data is used to produce asupport for the foot, a more effective device is produced.

It is also possible to design electromechanical contour sampling deviceswith variations like an array of trailing swing arms that translate inone axis while measuring the position of the swing arms to determine theshape of the subject surface.

Such devices have been successfully applied worldwide for themeasurement of the foot for the fabrication of custom foot supportappliances (foot orthotics).

Prior art devices used gauge pins which were urged upwards against theundersurface of the foot by a pneumatically actuated diaphragm. The footis placed against the top of the device and a device is slide under thetoes to restrict the upwards force of the gauge pins under said toes.

The gauge pins are urged up by a diaphragm until they contact theundersurface of the foot. A separate mechanism is used to “lock” orfreeze the gauge pins at the height attained. At this time the subjectfoot could be removed from the device. The gauge pins would retain theshape of the undersurface of the foot. A measurement means ormeasurement mechanism was used to determine the relative heights of thegauge pins. The resulting values were saved in a processor for storageand possibly subsequent manipulation and ultimately used to direct theoperation of a robotic milling machine to produce the finished custominsole.

The prior art devices therefore required the following steps involved inthe measurement of a foot: 1) place the foot on the device, 2) centerthe foot on the device using an incorporated heel guide, 3) slide thetoe plate into position to restrict upwards motion of the gauge pinsagainst the toes, 4) activate the diaphragm to urge up the gauge pins,5) activate the locking mechanism once the gauge pins have contacted thesubject foot, 6) remove the subject foot, 7) activate the measurementmechanism to determine the relative heights of the gauge pins, anddeactivate the locking mechanism and the diaphragm to reset the gaugepins for the next measurement. Each of the steps must be repeated foreach foot.

The prior art measurement mechanisms consisted of two measurements ofthe gauge pins in opposite directions. The processor uses these twomeasurements to determine an average value. It has been determined thatthe differences in these two measurements is so small as to be of littleaccuracy value. And by only measuring the gauge pins in one direction,at least 50% of the time used in measuring the gauge pins can be saved.It has also been determined that the measuring time can be furtherreduced by simply speeding up the scanning process. This reduction inscanning time eliminates the need for a locking mechanism.

The locking mechanism was a requirement in the prior art design due to anumber of factors. The measurement mechanism was fairly slow and therewas a risk of foot movement during the measuring process. Also, becauseit was desired to make a very accurate device, it was determined thatfor complete accuracy of gauge pin position, the pin must be locked inplace at some point in time and then measured.

If the measurement could be done faster, then there is less risk of footmovement during the scan. By changing some of the measurementtechniques, the scan time can be reduced by approximately 70%.

It is desirable to apply this technology to a broader market than simplyin the medical applications where it is used presently. Prior artdevices, however, do not lend themselves well to the broader (retail)market. The device is moderately fragile (each gauge pin can be shearedoff) and the top surface is subject to damage by accidental spillage ofliquids seeping into the interior of the device.

There is a need to provide contour sampling technology to a broadermarket than simply in the medical applications where it is usedpresently.

There is also a need to reduce the number of operator actions requiredto measure a foot to improve the simplicity of a contour samplingdevice.

There is a further need to enhance the prior art devices with new andunique improvements to address these shortcomings.

There is yet a further need to eliminate the need for a lockingmechanism or the need for a toe plate.

There is also a need to eliminate the concern for device contaminationand resulting failure due to contaminants being introduced through thetop surface of the device.

SUMMARY OF THE INVENTION

The present invention includes a system and method, including a contourmeasurement device, for measuring the contour of an object, preferably afoot. The foot measuring system includes a support surface for a foot, aplurality of movable measurement structures, an inflatable diaphragm forcontacting the first end of each structure and forcing a movement ofeach structure from an initial position toward a measurement position, ameasurement device for measuring the measurement position relative tothe initial position of each structure, after the movement of eachstructure, to determine a shape of the foot. Each structure of theplurality of movable structures has a first end and a second end.

The present invention also includes a method for measuring the contoursof a foot. The method includes placing the foot against a supportsurface of a foot measuring system, inflating a diaphragm to force aplurality of movable measurement structures through the surface andtoward the foot, moving each structure due to contact between the firstend of each structure and the diaphragm, detecting a change in positionof each the structure relative to an initial position of each thestructure, and measuring a shape of the foot based upon the change inposition of each the structure. Each structure of the plurality ofmovable structures has a first end and a second end, and each structureis limited in movement by contact between the second end and the foot.

The present invention also comprises a protective diaphragm to renderthe contour sampling device immune to contamination through the top ofthe device.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a system for measuring the contour of anobject.

FIG. 2 is a top view of the measurement system shown in FIG. 1.

FIG. 3 is a front view of the measurement system shown in FIG. 1.

DESCRIPTION OF THE INVENTION

The present invention provides a foot measuring system that includes asupport surface on which a foot is placed, a plurality of movablemeasurement structures each having a first end and a second end, aninflatable diaphragm for contacting the first end of each the structureand forcing a movement of each structure from an initial position towarda measurement position, and a measurement device for measuring themeasurement position relative to the initial position of each thestructure, after the movement of each the structure, to determine ashape of the foot.

In a preferred embodiment, the structures are elongated gauge pinsoriented in a direction perpendicular to a plane of the support surface.The support surface includes a plurality of holes through which thesecond end of each of the structures can be advanced toward the foot inresponse to the upward pressure exerted by the inflated diaphragm.

In another preferred embodiment of the present invention, the gauge pinsare measured by an array of electrostatic sensors that can sense therelative positions of an embedded metalized area on each gauge pin.These electrostatic sensors are mounted as a group on a circuit boardwith each sensor located at each gauge pin. This circuit board is movedin a direction corresponding to the lengthwise direction of the gaugepins. When the electrostatic sensor encounters the metalized area on agauge pin, the relative position of each pin is determined. The relativeposition, or measurement position is determined by the distance traveledby the circuit board along each gauge pin until the sensor at each gaugepin detects the metalized area. This distance will vary at each gaugepin, resulting in an array of values representing the shape of the foot.

The diaphragm is preferably connected to a bottom surface of themeasurement system to form an airtight cavity between portions of thediaphragm and the bottom surface. An air controller is connected to thecavity to controllably introduce air into the cavity to force the gaugepins upward toward the foot.

The system also includes a processor for controlling the air controller,the circuit board and sensors, and for at least retrieving measurementinformation. The processor may also be utilized to build a digitalrepresentation of the shape of the foot based on the measurementinformation. In one embodiment, the processor determines the initialposition of each the structure prior to inflating the diaphragm,inflates the cavity, compares the initial position of each the structurewith the measurement position of the each the structure after thediaphragm is inflated and each the structure stops moving do torestrictions caused by the inflated diaphragm and by the foot.

Embodiments of certain aspects of the measurement system, such asembodiments of the circuit board and gauge pins, are described in U.S.Pat. No. 5,640,779 to Rolloff et al., and U.S. Pat. No. 5,941,835 toSundman, both of which are incorporated in their entirety by referenceherein. Other embodiments of the circuit board and gauge pins aredescribed in U.S. Pat. No. 6,864,687 to Walker et al., which isincorporated in its entirety by reference herein.

The system also preferably includes a protective diaphragm located at ornear the surface that prevents contamination of the system through thetop of the system when the foot is placed on the surface, yet does notrestrict the movement of the plurality of structures beyond the surface.In a preferred embodiment, the contour sampling device of the presentinvention has incorporated therein a diaphragm disposed about the top ofthe unit between the gauge pins and the subject foot. The protectivediaphragm is preferably made from a stretchable and flexible material.This diaphragm may be mounted to a liquid shedding frame.

In order to reduce the likelihood that any restriction on the gauge pinexists as a result of the protective diaphragm, the protectivediaphragm's frame can be mounted above the top surface of the unit. Thismounting distance is a significant fraction of the dynamic range of thegauge pins. In a preferred embodiment this distance is in the rangebetween about 3-30 mm.

A toe plate may also be included, which is a device that is slid underthe forefoot, typically forward of the ball of the foot to prevent thetoes from being pushed up by the gauge pins. While a device such as atoe plate that selectively restricts the upward motion of the gauge pinscan be diagnostically useful, its placement requires some care and maytherefore be undesirable in a measurement device for the retail market.

In an alternate embodiment, the need for a toe plate has been eliminatedby placing the toes purposely off the end of the array of gauge pins.Pin locations are further tailored to prevent unnecessary upwards motionof the toe end of the foot. To assist the user in positioning the foot,a ridge of material in a shape designed to be similar to the shape ofthe transverse sulcus of the foot is provided. When the foot is placedagainst the top of the scanner, the toes are positioned forward of thisridge with the ball of the foot behind it. All areas behind the ridgewill be periodically sampled by the gauge pins.

The present invention also provides a method for measuring the contoursof a foot. The method includes placing the foot against the supportsurface of the foot measuring system, and inflating the diaphragm toforce the plurality of movable measurement structures, such as the gaugepins, through the surface a toward the foot to move each structure dueto contact between the first end of each structure and the diaphragm.Each structure is limited in its movement toward the foot by contactbetween the second end of the structure and the foot. The method furtherincludes detecting a change in position of each structure relative to aninitial position of each structure before the diaphragm was inflated,and measuring a shape of the foot based upon the change in position ofeach structure.

As discussed above, the measurement structures are preferably elongatedgauge pins used in conjunction with a circuit board having a pluralityof sensors, each of which corresponds to a single gauge pin and senses aselected area of each gauge pin to determine a position of each gaugepin. In another embodiment, the method includes determining the initialposition of each structure prior to inflating the diaphragm, followed bycomparing the initial position of each structure with a position of eachstructure after the diaphragm is inflated and each structure stopsmoving do to restrictions caused by the inflated diaphragm and by thefoot.

The method described above may be performed a single time to measure theshape of the foot, or may be performed multiple times on the foot. Asingle measurement would be useful to save time in taking a measurementof the shape of the foot. Multiple measurements can also be performed inrelatively quick succession to ensure that the measurement is accurate,and/or to determine whether the foot moved during measurement.

FIG. 1 is a side view of a system for measuring the contour of anobject. FIG. 2 is a top view of the measurement system shown in FIG. 1.FIG. 3 is a front view of the measurement system shown in FIG. 1.

A system 100 for measuring the contours of an object, such as a foot105, is shown in FIGS. 1-3. System 100 includes an electrostaticscanning matrix circuit board 110, a reference top surface 115,leadscrews 120, gauge pins 125, control electronics 130, an aircontroller 135, an air cavity 140, and a top protective diaphragm 145.

Reference top surface 115 is the mechanical zero elevation for thescanning mechanism as well as the top structural member of the scanner.Top surface 115 includes a series of holes 170 corresponding to each ofgauge pins 125 so that gauge pins 125 can be advanced vertically fromtop surface 115 toward the contour of foot 105. Locating rib 150 islocated on top surface 115 to assist subject in locating foot 105 in alengthwise direction.

Top diaphragm 145 protects electronic components such as circuit board110 from contamination. Top diaphragm 145 is preferably fabricated froma stretchable, flexible material, such as latex, rubber or otherrubber-like materials.

Top diaphragm 145 is preferably attached to a diaphragm clamp 175 sothat top diaphragm 145 is secured to system 100. Diaphragm clamp 175extends around at least an area encompassing holes 170 so thatcontaminants cannot penetrate system 100 and contaminate sensitivecomponents such as circuit board 110. Diaphragm clamp 175 is attached totop surface 115 such as by an adhesive, screws or clamps. As shown inFIG. 1, at least a portion of diaphragm clamp is elevated above topsurface 115, so that top diaphragm 145 does not restrict gauge pins 125.Top diaphragm 145 may extend from the sides of elevated diaphragm clamp175, or a sidewall may be included to prevent contaminates from enteringsystem 100.

Each of gauge pins 125 include a reference area 155. Reference area 155may be an area coated with a metallic material such as metal foil.Circuit board 110 includes sensors for detecting reference area 155 oneach gauge pin 125.

Air cavity 140 includes a rigid lower half 160 and a preferably highlycompliant diaphragm top 165 that urges gauge pins 125 upwards when airis introduced into cavity 140. Air controller 135, such as an aircompressor, is provided to introduce air into cavity 140.

Leadscrews 120 are provided for translating circuit board 110 in anup/down direction to determine relative heights of each gauge pin 125above top surface 115, based on a relative position of each referencearea 155.

In use, subject foot 105 is placed on reference top surface 115, takingreasonable care to be in the approximate center. Locating rib 150 may beused to assist in positioning foot 105 properly on top surface 115.

Air controller 135 is activated to introduce air into air cavity 140,which in turn forces gauge pins 125 upward. Each gauge pin 125 contactsa different point on the contour of foot 105, and the upward motion ofeach gauge pin is inhibited by the contour surface of foot 105.Leadscrews 120 are activated to urge circuit board 110 upward andmeasure the relative position of each reference area 155. Preferably,control electronics 130 activate and control air controller 135,leadscrews 120 and circuit board 110 to acquire a measurement of thecontour of foot 105. The position information may then be sent to aprocessor to be used for creating a digital impression of the contour offoot 105.

The method can be initiated by a user, for example, by activating a“Scan” macro. In response, the system will automatically perform thefollowing steps: a) activate air controller 135 to activate and inflatediaphragm 165, b) optionally activate a locking mechanism to lock thegauge pins in place, c) activate the measurement device to take ameasurement of the foot, and d) deactivate air controller 135 anddiaphragm 165, and if applicable, deactivate the locking mechanism.

Nothing in this disclosure should be construed as limited to anyspecific method of mechanical or electromechanical measurement, or anyspecific measurement tool such as gauge pins. The improvements providedby the present invention may be utilized with any measurement techniquethat make it more practical in a retail oriented use. Furthermore, thepresent invention can be utilized to measure any object that can beplaced on the support surface. The present invention is not limited tomeasuring feet.

It should be understood that various alternatives, combinations andmodifications of the teachings described herein could be devised bythose skilled in the art. The present invention is intended to embraceall such alternatives, modifications and variances that fall within thescope of the appended claims.

1. A foot measuring system comprising: a support surface for a foot; aplurality of movable measurement structures, wherein each structure ofsaid plurality of movable structures has a first end and a second end;an inflatable diaphragm for contacting said first end of each saidstructure and forcing a movement of each said structure from an initialposition toward a measurement position; a protective diaphragm locatedat or near said surface that prevents contamination of said system whensaid foot is placed on said surface, yet does not restrict said movementof said plurality of structures beyond said surface; and a measurementdevice for measuring said measurement position relative to said initialposition of each said structure, after said movement of each saidstructure, to determine a shape of said foot.
 2. The system of claim 1,wherein said movable structures are elongated pins oriented in adirection perpendicular to a plane of said support surface.
 3. The footmeasuring system of claim 1, wherein said support surface includes aplurality of holes through which said second end of each of saidstructures can be advanced toward said foot.
 4. The system of claim 1,wherein said movement of each said structure is restricted by contactbetween said second end and said foot.
 5. The system of claim 1, whereinsaid measurement device includes a plurality of sensors that sense aselected area of each said structure to determine a relative changebetween said measurement position and said initial position of each saidstructure after said diaphragm is inflated.
 6. The system of claim 5,wherein said plurality of sensors are positioned in an array on acircuit board, and wherein said selected area is a metalized areadetectable by a respective sensor of said plurality of sensors.
 7. Thesystem of claim 5, wherein said measurement device performs saidmeasurement once or multiple times to determine said shape of said foot.8. The system of claim 5, further comprising a processor operativelyconnected to said plurality of sensors, wherein said processor:determines said initial position of each said structure prior toinflating said diaphragm; compares said initial position of each saidstructure with said measurement position of each said structure aftersaid diaphragm is inflated and each said structure stops moving do torestrictions caused by said inflated diaphragm and by said foot; andconstructs a digital impression based on said change of position of eachsaid structure.
 9. The system of claim 1, further comprising: a bottomsurface in a substantially airtight connection with at least a portionof said diaphragm to form an airtight cavity bounded by said bottomsurface and said diaphragm; and an air controller to introduce air intosaid cavity, wherein introducing air into said cavity applies a force toeach said structure by said diaphragm to force said movement of eachsaid structure toward said foot.
 10. The system of claim 1, wherein saidprotective diaphragm is made from a stretchable and flexible material.11. The system of claim 1, further comprising a ridge on said supportsurface to aid in properly positioning said foot on said supportsurface.
 12. The system of claim 1, further comprising a device toselectively restrict said movement of one or more of said plurality ofmeasurement structures.
 13. A method for measuring the contours of afoot, comprising: placing said foot against a support surface of a footmeasuring system; inflating a diaphragm to force a plurality of movablemeasurement structures through said surface and toward said foot,wherein each structure of said plurality of movable structures has afirst end and a second end; moving each said structure due to contactbetween said first end of each said structure and said diaphragm,wherein each said structure is limited in movement by contact betweensaid second end and said foot; detecting a change in position of eachsaid structure relative to an initial position of each said structure;and measuring a shape of said foot based upon said change in position ofeach said structure, wherein said foot measuring system further includesa protective diaphragm located at or near said surface that preventscontamination of said system when said foot is placed on said surface,yet does not restrict a movement of said plurality of structures beyondsaid surface.
 14. The method of claim 13, wherein said movablestructures are elongated pins oriented in a direction perpendicular to aplane of said support surface.
 15. The method of claim 13, wherein saidsupport surface includes a plurality of holes through which said secondend of each of said structures is advanced toward said foot.
 16. Themethod of claim 13, further comprising: including a plurality of sensorsthat sense a selected area of each said structure; and determining saidinitial position of each said structure prior to inflating saiddiaphragm.
 17. The method of claim 16, wherein said plurality of sensorsare positioned in an array on a circuit board, and wherein said selectedarea is a metalized area detectable by a respective sensor of saidplurality of sensors.
 18. The method of claim 13, wherein detecting saidchange in position is accomplished by: comparing said initial positionof each said structure with a position of each said structure after saiddiaphragm is inflated and each said structure stops moving due torestrictions caused by said inflated diaphragm and by said foot.
 19. Themethod of claim 18, wherein measuring said shape of said foot includesconstructing a digital impression based on said change of position ofeach said structure.
 20. The method of claim 13, wherein at least aportion of said diaphragm forms an airtight cavity bounded by a bottomsurface, and wherein said diaphragm is inflated by introducing air intosaid cavity.
 21. The method of claim 13, wherein said method isperformed once or multiple times to determine said shape of said foot.